On the other hand, HAPS, often deployed as quasi-stationary modules in the stratospheric layer, can provide high capacity and improved coverage while offering a longer flying duration [1]}. HAPS, therefore, emerges nowadays as a vital network component of VHetNets, integrating the terrestrial and aerial layers seamlessly and improving the network's flexibility, resilience, and robustness. HAPS has particularly emerged recently
as a key enabler for achieving the ubiquitous connectivity goals of 6G networks [1]}. Given its strategic hovering altitude, HAPS is considered the medium infrastructure that seamlessly connects space-borne, airborne, and terrestrial communication systems. More specifically, HAPS-assisted networks support mobile and fixed users, enabling the networks to satisfy different service demands. HAPS-assisted networks are economical solutions that provide large capacity to hyper-digitized areas while ensuring connectivity and coverage to under-served and rural areas [3]}. HAPS-assisted networks indeed have the potential to improve the accessibility and quality of communication services by complementing and consolidating TNs [1]}, [5]}.
